See also: The Hitchhiker’s Guide to Python

IDE’s like PyCharm will complain when this is attempted, in which you’ll see messages like the following:

Default argument value is mutable...

Inspection info: This inspection detects when a mutable value as list or dictionary is detected in a default value for an argument. Default argument values are `evaluated only once at function definition time`, which means that modifying the default value of the argument will affect all subsequent calls of the function.

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